The present invention relates to an electrical switch device.
Such a switch device results, for example, from DE 10 2007 040 714 A1. This known switch device covers a contact system comprising a movable switch contact and two fixed contacts. The switch device furthermore has a movable actuator for switching the contact system. When switching the contact system, the movable switch contact is movable such that it adjoins to a first fixed contact in a first switch position and to the second fixed contact in a second switch position.
The switch contact has the shape of a slider, and the fixed contacts are designed as contact surfaces such that the slider interacts with the contact surfaces upon switching. In addition, a leaf spring is provided which is coupled with the slider and interacts with the actuator for resetting.
Such switch devices which are designed as micro switch devices or snap-action switch devices are used for the switching of power currents or signal currents, for example in motor vehicles.
The technical problem of the present invention is to develop such an electrical switch device in such a manner that its switch contacts have precisely predefined switch positions upon switching in the switch positions of the contact system.
This technical problem is solved by means of an electrical switch device comprising the features of patent claim 1.
The essential advantage of the present invention is that the present electrical switch device ensures precisely predefined switch positions upon switching due to its specific configuration comprising a so-called snap-action element. Switching errors are thus avoided. Due to the combination with said snap-action element, it is ensured that during the switching operation, on the one hand, the switching power is at first transmitted smoothly and resiliently from the actuator to the switching system, and, on the other hand, the switch positions of the sliding contact are subsequently reached and/or adjusted precisely. In this respect, it must be made sure that the sliding contacts always resiliently adjoin to the fixed contacts.
Another essential advantage of the switch device according to the invention is that the actuator is moved linearly, which is why the overall switch device operates precisely and can be constructed in a less bulky and more space-saving manner.
The electrical switch device according to the invention comprises a contact system having at least one movable sliding contact and at least one first fixed contact as well as a second fixed contact. In addition, the switch device according to the invention comprises a movable actuator for switching the contact system, wherein, when switching the contact system, the switch contact is movable such that it adjoins to the first fixed contact in a first switch position and to the second fixed contact in a second switch position. The contact system resiliently preloads the sliding contact against the first fixed contact in the first switch position and against the second fixed contact in the second switch position. In case of pressurization, the actuator moves the sliding contact mainly linearly from the first switch position to the second switch position. In the first switch position, the actuator adjoins to a snap-action element having a stable position and actuates the latter from its stable position to an instable position when switching over to the second switch position, wherein the snap-action element returns to the stable position upon completion of pressurization by means of the actuator.
In a preferred, constructively simple and effective embodiment of the invention, the actuator has a spring part at the one end of which the sliding contact is arranged, wherein the other end of the spring part is fixed to a pencil-shaped part mounted in the disk element on one side of a disk element, and wherein an area of said pencil-shaped part protruding beyond the disk element on the other side of the disk element forms a connecting part.
In an advantageous further embodiment of the invention, opposite to the pencil-shaped part, a further pencil-shaped part, at the one end of which a further sliding contact is arranged, is provided on the disk element. The other end of the further spring part is fixed on one side of the disk element to a further pencil-shaped part mounted in the disk element, wherein an area of the pencil-shaped part protruding beyond the disk element on the other side of the disk element forms a further connecting part.
In an advantageous further embodiment of the invention, the other ends of the rod-shaped spring part and the further rod-shaped spring part can be connected to each other by means of a rod-shaped part. In this way, the sliding contact, the spring part, the rod-shaped part, the further spring part and the further sliding contact can be formed as a single piece, in particular of an electrically conductive metal spring wire part.
The spring part and/or the further spring part can be attached to the corresponding pencil-shaped parts in a particularly simple and effective manner by winding or bending their other end portions round the corresponding pencil-shaped parts in each case. At the same time, the electrical contacts are established between the spring parts and the pencil-shaped parts.
Preferably, the actuator has the shape of a block which is expediently made of a plastic material and which, on the side facing the disk element, has a peg-shaped area adjoining to the snap-action element. A pressure spring is provided preloading the actuator towards the snap-action element. The rod-shaped spring part is attached to one side of the actuator. If the further spring part is also provided, the latter is attached to the side of the actuator opposite to the one side of the actuator. It is thus achieved that the block-shaped actuator is surrounded in a frame-like manner by the spring parts and held between the latter. Upon actuation of the actuator, the sliding contacts moulded onto the spring parts advantageously perform a mainly linear movement.
Preferably, the pressure spring is arranged in a receiving space of the actuator, with one end of the pressure spring resting on the bottom of the receiving space and the other end of the pressure spring resting on a tappet element held in the case of the switch device and protruding outwards through an opening of an upper case part of the case of the switch device for actuation. In a further embodiment of the invention, the other end of the pressure spring presses against a flange part of the tappet element, which can be pressed against the rim of the recess due to the force of the pressure spring. Advantageously, it is thus achieved that the force acting on the tappet element is transmitted smoothly and in a well-defined manner via the peg-shaped element to the snap-action element.
Advantageously, the snap-action element is arranged and/or attached to the disk element above a recess, with the snap-action element being capable of partly engaging with the recess in the instable position. This enables a simple movement of the snap-action element between its stable and instable position.